#include<iostream>

using namespace std;

typedef long long LL; 

const int N =1e5+10;

int a[N],tmp[N];


LL mgsort(int q[],int l,int r)
{
    if(l>=r) return 0;

    int mid=l+r>>1;

    LL res=mgsort(q,l,mid)+mgsort(q,mid+1,r);

    int k=0,i=l,j=mid+1;
    while(i<=mid&&j<=r){
    	if(q[i]<=q[j]) tmp[k++]=q[i++];
        else{
        	res+=mid-i+1;
        	tmp[k++]=q[j++];
		}
	}
        
    while(i<=mid) tmp[k++]=q[i++];
    while(j<=r) tmp[k++]=q[j++];

    for (i=l,j=0;i<=r;i++,j++) q[i]=tmp[j];
    
    return res;
}


int main()
{
    int n;
    scanf("%d",&n);
    for(int i=0;i<n;i++ ) scanf("%d",&a[i]);

    cout<<mgsort(a,0,n-1)<<endl;
    
    return 0;
}

